to give me a point of reference, what was the factory set LHT/HHT and what all combinations did you try?
FYI, On my unit anyways, just restarting is not a trigger for the ignitor to start. I think there is some logic that the ignitor only comes on if temp is less X. I don't know what X is, but it is pretty low.
have you successfully grilled or baked at higher temps?
are your pellets fresh/new? are they totally dry?